Quartz crystal oscillator has been used for several decades and played an important role in the electronics industry for its high frequency stability. Especially under a high development of the information technology industry, this quartz crystal oscillator is full of vitality much more. The quartz crystal oscillators served as a standard frequency source or a pulse signal source provide a frequency reference in telecommunications, satellite communications, Mobile Phone System, Global Positioning System, navigation, remote control, aerospace, high-speed computer, precise measuring instrument and consumable electronic products, which can not be replaced by other oscillators. The quartz crystal oscillators generally include non-temperature compensated crystal oscillator, temperature compensated crystal oscillator, voltage-controlled crystal oscillator, oven controlled crystal oscillator, and digital/μp compensated crystal oscillator. Therein the oven controlled crystal oscillator has the highest frequency stability and the highest precision, and the performances of aging rate, temperature stability, long-term stability, and short-term stability are excellent, therefore the oven controlled crystal oscillator is widely used in electronic equipments such as Global Positioning System, communications, measurement, telemetry and remote, spectrum and network analyzer.
A conventional oven controlled crystal oscillator commonly uses a double in-line package, and FIGS. 1a-1b show a common oven controlled crystal oscillator. The oven controlled crystal oscillator 1 includes a crystal oscillator body 11 and a base 12, and the crystal oscillator body 11 is fixed on the base 12. The base 12 includes a base plate 121, functional pins 122 and base protrusions 123. Concretely, the functional pins 122 are electrically connected with a crystal oscillation circuit (not shown), and a circular insulating layer 124 is formed around the functional pin 122 so as to insulate against the metal base plate 121. When the functional pins 122 of the oven controlled crystal oscillator 1 are directly soldered to the client products by an inserting way, the base protrusions 123 can prevent the oven controlled crystal oscillator 1 from directly contacting the products. With the oven controlled crystal oscillator soldered to the product, on one hand, the height thereof is bigger which goes against the compact manufacturing of the electronic product; on the other hand, faulty soldering may appear on the functional pins 122 which causes a bad contact on the oven controlled crystal oscillator, and decreases the working stability. In addition, the assembly using in-line package of the oven controlled crystal oscillator needs manual operation, thus the cost is high and the production efficiency is quite low.
For improving the production efficiency and decreasing the cost, the manufacturer of the oven controlled crystal oscillator improved the current oven controlled crystal oscillator with the in-line package. Referring to FIGS. 2a-2b, the oven controlled crystal oscillator 2 also includes a crystal oscillator body 21 and a base 22. But the difference compared to the oven controlled crystal oscillator 1 is that, the functional pins 222 of the oven controlled crystal oscillator 2 are firstly soldered to a conversion printed circuit board 225, and then the oven controlled crystal oscillator 2 is soldered to the client product via pads 226 on the conversion printed circuit board 225, so as to obtain a surface mounted oven controlled crystal oscillator. However, with the above-mentioned surface mounted way, since the weight of the oven controlled crystal oscillator is heavy, thus the oscillation thereof may invalidate the electric connection at the pins when on operation. Thus, the oven controlled crystal oscillator using the surface mounted way ordinarily has a small cubage. At the same time, as shown in FIG. 2a, the height of the oven controlled crystal oscillator 2 is still big as a portion of the functional pins is exposed outside. Moreover, when the client products undergo a reflow oven, the pins on the conversion printed circuit board 225 may cause faulty soldering as the solder melts under a high temperature. Or a problem that the oven controlled crystal oscillator 2 may be deflective due to the weight itself will happen. Furthermore, the manufacturing process of this oven controlled crystal oscillator 2 is complicated, which goes against the mechanization batch production with a high efficiency, and the manufacturing cost is high.
Thus, there is a need for an improved surface mounted oven control crystal oscillator with high stability, simple manufacturing process and high-efficiency assembly to overcome the above drawbacks.